Phase difference layer laminated body for three dimensional liquid crystal display device and manufacturing method thereof

ABSTRACT

A phase difference layer laminated body used in a three-dimensional liquid crystal display device, wherein unit cells are divided into groups for left and right eyes, which are given different degrees of polarization, thereby creating a three-dimensional image, further wherein the phase difference layer laminated body has a base material having orientability, and a phase difference layer made of a liquid crystal material that can form a nematic phase and formed in a pattern with two different portions, and the liquid crystal material in each of two different portions is oriented to have different refractive index anisotropy each other that conforms to the two different degrees of polarization and fixed as it is.

This application is a Divisional of 13/728,160, filed Dec. 27, 2012which is a Divisional of 12/923,312, filed Sep. 14, 2010, which in turnis a Continuation-in-Part of 12/073,636, filed Mar. 7, 2008, which inturn is a Continuation of Ser. No. 11/602,382, filed Nov. 21, 2006,which in turn is a Continuation of Ser. No. 10/473,215, filed Oct. 30,2003, which in turn is a National Phase of International PatentApplication No. PCT/JP02/11601, filed Nov. 7, 2002, which claimspriority of Japanese Patent Application Nos. 2001-343873, filed Nov. 8,2001 and 2002.259150, filed Sep. 4, 2002. The disclosures of theseapplications are incorporated herein by reference in their entirety.

TECHNICAL FIELD

The present invention relates to a phase difference layer laminated bodyfor a three dimensional liquid crystal display device which offers highorientation freedom and allows easy patterning, a manufacturing methodthereof, a manufacturing method of an optical oriented film used for aphase difference layer laminated body, a liquid crystal cell including aphase difference layer laminated body and a three dimensional liquidcrystal display device.

BACKGROUND ART

Phase difference film used for liquid crystal displays and the like isconventionally made of a polymer film which is stretched in certaindirections to orient the main chains of the polymer in these directionsso that the polymer film exhibits refractive index anisotropy.

According to this method, the polymer film can be provided withrefractive index anisotropy with relative ease; the method was excellentin that it enabled easy formation of phase difference films.

However, this method only allows fabrication of phase difference filmsin which the main chains of polymer are oriented in the directions ofstretch, and therefore the problem was that the orientation of resultantphase difference films was limited only to directions parallel to thesurface of the phase difference film.

Meanwhile, phase difference films having vertical polymer orientationrelative to the surface, or various other orientation directions, arenow in demand; the problem with the above method for obtaining phasedifference films by stretching polymer films is that it cannot meet suchdemand because of its little freedom in setting orientation direction.

In a multi-domain type liquid crystal display element, for example, inwhich each unit cell is divided into a plurality of regions withdifferent directions of liquid crystal directors, optical compensationwith the conventional phase difference film was, while favorable in someregions, not necessarily satisfactory in other regions.

DISCLOSURE OF THE INVENTION

The present invention has been devised in view of the above problems,and a main object thereof is to provide a phase difference layerlaminated body which has very high freedom of molecular orientation inits phase difference layer and which can be manufactured with ease, amanufacturing method thereof, and a liquid crystal display device.

To achieve the above object, the present invention provides (1), a phasedifference layer laminated body used in a three-dimensional liquidcrystal display device, wherein unit cells are divided into groups forleft and right eyes, which are given different degrees of polarization,thereby creating a three-dimensional image, further wherein the phasedifference layer laminated body has a base material havingorientability, and a phase difference layer made of a liquid crystalmaterial that can form a nematic phase and formed in a pattern with twodifferent portions, and the liquid crystal material in each of twodifferent portions is oriented to have different refractive indexanisotropy each other that conforms to the two different degrees ofpolarization and fixed as it is. According to the invention, since aliquid crystal material that can form a nematic phase is used for thephase difference layer, by suitably selecting the type of liquid crystalmaterial and the base material having orientability, it is possible todetermine orientation directions with ease, and therefore the phasedifference layer laminated body thus obtained can be applied to a threedimensional liquid crystal device.

Furthermore, the present invention provides (7), a method formanufacturing a phase difference layer laminated body used in athree-dimensional liquid crystal display device, wherein unit cells aredivided into groups for left and right eyes, which are given differentdegrees of polarization, thereby creating a three-dimensional image,characterized by having:

-   -   a base material preparation step of preparing a base material;    -   an application step of applying a refractive index anisotropic        material having an ability of providing refractive index        anisotropy on the base material for forming a refractive index        anisotropic material layer;    -   an orientation processing step of performing orientation        processing to the refractive index anisotropic material layer so        as to form a pattern with two portions oriented in two different        directions;        an orientation fixing step of fixing the orientation of the        refractive index anisotropic material layer that has undergone        the orientation processing in the orientation processing step.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view showing one example of aphase difference layer laminated body of the invention;

FIG. 2 is a schematic cross-sectional view showing another example of aphase difference layer laminated body of the invention;

FIG. 3 is a schematic cross-sectional view showing yet another exampleof a phase difference layer laminated body of the invention;

FIG. 4 is a schematic plan view of an oriented film with patternedorientation directions;

FIG. 5 is a diagram showing process steps of one example of a method formanufacturing a phase difference layer laminated body of the invention;

FIG. 6 is a schematic cross-sectional view showing one example of anoptical element using a phase difference layer laminated body of theinvention;

FIG. 7 is a schematic cross-sectional view showing another example of anoptical element using a phase difference layer laminated body of theinvention;

FIG. 8 is a perspective view of a liquid crystal display device havingthe phase difference layer laminated body of the invention and capableof displaying three-dimensional images, partially shown to a largerscale;

FIG. 9 is a perspective view showing a patterning process of aphoto-oriented film;

FIG. 10 is an exploded perspective view showing the schematicconstruction of a liquid crystal display device according to oneembodiment of the invention;

FIG. 11 is an enlarged side cross-sectional view showing the essentialconstruction of the liquid crystal display device;

FIG. 12 is a perspective view showing oriented compensation regions inthe liquid crystal display device; and

FIG. 13 is a perspective view showing oriented display regions andoriented compensation regions in the liquid crystal display device.

BEST MODE FOR CARRYING OUT THE INVENTION

The phase difference layer laminated body, and the manufacturing methodthereof, according to the invention, will be hereinafter describedrespectively.

A. Phase Difference Layer Laminated Body

The phase difference layer laminated body of the invention ischaracterized by having a base material having orientability, and aphase difference layer made of a liquid crystal material that can form anematic phase and formed on the base material such as to have refractiveindex anisotropy.

With such a construction of the phase difference layer laminated body ofthe invention, if the orientability of the base material is such that itcan orient liquid crystal at a preset angle relative to the phasedifference layer surface, and a phase difference layer laminated body isformed with the use of liquid crystal material that is orientable insuch a manner, a phase difference layer oriented at a preset angle tothe surface can readily be provided. A phase difference layer laminatedbody having such a phase difference layer will find new applications inaddition to the conventional ones.

This phase difference layer laminated body will further be describedbelow with reference to the drawings. FIG. 1 shows one example of aphase difference layer laminated body of the invention, in a state inwhich a phase difference layer 2 of liquid crystal material that canform a nematic phase is formed on a base material 1 having surfaceorientability such that the liquid crystal has refractive indexanisotropy.

The invention includes another construction such as the one shown inFIG. 2 wherein the base material 1 having the above orientability isconstituted by a transparent substrate 3 and an oriented film 4 formedthereon. The use of such an oriented film 4 will make the orientationfreedom of the phase difference layer 2 extremely high as will bedescribed later, which in turn enhances the orientation freedom of thephase difference layer laminated body to a very high degree.

Also, in the present invention, the phase difference layer formed on theorientated film 4 may have a certain pattern as shown in FIG. 3. Athree-dimensional display device or the like, for example, which enablesdisplay of three-dimensional images by differing the polarization forthe left and right eyes, requires a phase difference layer laminatedbody having a patterned phase difference layer; the phase differencelayer laminated body shown in FIG. 3 can be used in such athree-dimensional display device or the like.

Various elements of the phase difference layer laminated body of theinvention are described below in more detail.

1. Phase Difference Layer

The phase difference layer laminated body of the invention ischaracterized in that a phase difference layer 2 of a liquid crystalmaterial that can form a nematic phase is formed on a base material 1having orientability such that the liquid crystal has refractive indexanisotropy, as shown in FIG. 1.

(Liquid Crystal Material)

For the material forming the phase difference layer, a liquid crystalmaterial is used as noted above. The term “liquid crystal material” inthis invention refers to a material that can transform into a liquidcrystal phase at a certain temperature; more particularly, thisinvention is characterized in that this liquid crystal phase of thematerial is a nematic phase.

In the present invention, as will be described in more detail laterunder the section of “manufacturing method of a phase difference layerlaminated body,” a liquid crystal material is transformed into a liquidcrystal phase upon a base material having orientability, whereby theliquid crystal molecules in the phase difference layer are oriented toexhibit refractive index anisotropy. Therefore, the upper limit of theabove-mentioned temperature should not be limited to a specific valueand may be set such that no damage is inflicted on the base material,or, in the case of an oriented film formed on a transparent substrate aswill be described later, on the transparent substrate and oriented film.More specifically, a liquid crystal material that transforms into aliquid crystal phase at a temperature of 120.degree. C. or lower, morepreferably 100.degree. C. or lower, can favorably be used in respect ofeasy control of processing temperature and maintenance of dimensionalprecision.

The lower limit, on the other hand, of the temperature at which theliquid crystal phase forms, should be set so that the liquid crystalmaterial can maintain its orientation, subject to the temperature rangefor the application as a phase difference layer laminated body.

a liquid crystal material in an application as a phase difference layerlaminated body can take two different states: In this invention, both anon-polymerizable polymer liquid crystal material and a polymerizableliquid crystal material can be used as will be described later. In thecase of a polymerizable liquid crystal material, when forming the phasedifference layer, as will be described in more detail under the sectionof “manufacturing method of phase difference layer laminated body,”polymerization is achieved by irradiating the material with theactivating radiation beam. In this case, therefore, the liquid crystalmaterial used in the phase difference layer laminated body has alreadybeen polymerized, its orientation being fixed. Namely, in the case ofthe polymerizable liquid crystal material, there is no limitation on thelower limit of the temperature at which the material transforms into aliquid crystal phase.

On the other hand, in the case of the non-polymerizable polymer liquidcrystal material, the liquid crystal phase is in the glass state whenused as the phase difference layer laminated body. That is, if ittransforms into an isotropic state due to a rise in temperature duringstorage or use, its orientation will be in disorder and the phasedifference layer can no longer be put in use. Thus, in the case of usinga non-polymerizable polymer liquid crystal material in the invention, itis preferred that the material transform into an isotropic phase attemperatures equal to or more than a preset value. The lower limit ofthe temperature at which the material transforms into an isotropic phasein this case depends on the purposes of use, but generally speaking, itis at least 80.degree. C., or more preferably, 100.degree. C. or more.

The liquid crystal material that can form a nematic phase used in thisinvention can either be a polymerizable liquid crystal material andnon-polymerizable polymer liquid crystal material as noted above.

For the polymerizable liquid crystal material, any of polymerizableliquid crystal monomer, polymerizable liquid crystal oligomer, andpolymerizable liquid crystal polymer may be used. For thenon-polymerizable polymer liquid crystal material, on the other hand,because of the above-mentioned requirement for the maintenance oforientation under various temperatures during storage or use of thephase difference layer laminated body, a liquid crystal material havinga relatively high isotropic transition temperature should preferably beused.

In this invention, particularly, a polymerizable liquid crystal materialis most preferably used. This is because the use of polymerizable liquidcrystal material, whose orientation can be fixed by polymerization thatis achieved by irradiating the material with the activating radiationbeam as will be described later, enables easy orientation of the liquidcrystal at low temperatures, and also because it can be used withouttemperature limitations or other restrictions due to the fixedorientation when put in use.

More particularly, a polymerizable liquid crystal monomer is preferablyused in this invention. This is because a polymerizable liquid crystalmonomer lets itself to be oriented at a lower temperature than otherpolymerizable liquid crystal materials such as polymerizable liquidcrystal oligomers or polymers; it also has high orientation sensitivity,allowing the orientation to be readily achieved.

As one example of the polymerizable liquid crystal material, thecompounds included in the general formula 1 below or a mixture of two ormore of the following compounds may be used. In the case of liquidcrystal monomers expressed by the general chemical formula 1, X ispreferably an integer of 2 to 5.

In addition, polymerizable liquid crystal oligomers or polymers can alsobe used in this invention. Any one of known polymerizable liquid crystaloligomers or polymers may suitably be selected and used.

Furthermore, photopolymerization initiators may be used as required inthis invention. Photopolymerization initiator may not always benecessary as with the case with, for example, polymerization ofpolymerizable liquid crystal material by irradiation of electron beams,but it is normally used for the promotion of polymerization in thecommonly used method of curing by irradiation of, e.g., ultravioletrays.

Also, a sensitizing agent may be added in addition to thephotopolymerization initiator, in an amount that does not inhibitachievement of the object of the invention.

Photopolymerization initiator is generally added in a range of 0.01 to20% by weight; preferably, it is added in a range of 0.1 to 10% byweight, and more preferably 0.5 to 5% by weight, to the polymerizableliquid crystal material of the invention.

On the other hand, non-polymerizable liquid crystal materials can alsobe used in this invention, as noted above. Any such liquid crystalmaterial can be used as long as it satisfies the requirement that theorientation of liquid crystal does not change during the use or storagethereof as a phase difference layer laminated body as described above;generally, however, polymer material is preferable in terms of thetemperatures at which the polymer material transforms into a liquidphase or a liquid crystal phase. Any commonly used liquid crystalmaterial that can form a nematic phase in a liquid crystal phase can beused, including both main-chain and side-chain liquid crystal polymers.

More specifically, typical examples of main-chain liquid crystalpolymers are polymers such as polyesters, polyamides, polycarbonates,and polyesteramides.

Further, examples of side-chain liquid crystal polymers are those thathave a backbone structure such as polyacrylate, polymethacrylate,polysiloxane, and polymalonate and a low molecular weight liquid crystalcompound (mesogen group) comprising a para-substituted cyclic compoundor the like as a side chain, with or without a spacer comprisingconjugated atoms.

(Refractive Index Anisotropy)

In this invention, the above-mentioned material must be formed into aphase difference layer having refractive index anisotropy. Refractiveindex anisotropy differs depending on the liquid crystal material beingused and the orientability of the base material surface, but thefollowing can generally be said: The difference .DELTA.n, expressed as.DELTA.n=|n.sub.x−n.sub.y|, between the indexes of refraction n.sub.xand n.sub.y in an X axis and Y axis on a plane parallel to theorientation of the polymer, the X-axis being orthogonal and Y-axis beingparallel to the orientation direction, should preferably be 0.05 ormore, or more preferably 0.1 or more. A phase difference layer havingless refractive index anisotropy than that may present a problem inregard to thickness or the like in actual applications.

(Patterned Phase Difference Layer)

In this invention, the phase difference layer formed of theabove-mentioned liquid crystal material may have a certain pattern.

A phase difference layer laminated body having a patterned phasedifference layer is preferably used in, for example, a three-dimensionalliquid crystal display device or the like, wherein unit cells aredivided into groups for left and right eyes, which are given differentdegrees of polarization, thereby creating a three-dimensional image.Such a patterned phase difference layer laminated body wasconventionally made by manual cutting and bonding of phase differencelayer films comprising common stretched films. Such technique wasproblematic in terms of cost and had limitations on the formation ofhighly precise patterns.

The present invention overcomes this problem and provides a phasedifference layer laminated body in which a phase difference layer isformed on the base material in a highly precise pattern.

In this invention, the pattern formation method differs depending on thetype of liquid crystal material. That is, the pattern formation methodfor a polymerizable liquid crystal material is different from that for anormal liquid crystal material.

The pattern formation method will be described later in more detailunder the section “manufacturing method of a phase difference layerlaminated body;” in short, in the case of the polymerizable liquidcrystal material, the irradiation of activating radiation beam for thefixing of the orientation of liquid crystal material is made in acertain pattern, and after the polymerization, uncured portions ofliquid crystal material are removed by a solvent; patterning of thephase difference layer is thus readily achieved.

In this invention, amongst the polymerizable liquid crystal materialsmentioned above, a polymerizable liquid crystal monomer is preferablyused because of the ease of the patterning. With a polymerizable liquidcrystal monomer, development is easy, the pattern is more clear-cut, andformation of more precise pattern is possible.

On the other hand, a photolithography technique using a photoresist, ora method of applying a normal liquid crystal material in a certainpattern by a nozzle discharge or printing technique may be adopted forthe pattern formation method in the case of using a non-polymerizablepolymer liquid crystal material.

In the case of forming the phase difference layer laminated body in apattern, the pattern may be any pattern, for example, striped orzigzagged.

2. Base Material Having Orientability

The phase difference layer laminated body of the invention is comprisedof a base material 1 having orientability, on which is formed theabove-described phase difference layer 2, as shown in FIG. 1.

For the base material having orientability, there are two cases: One isthat the base material 1 itself has orientability, as shown in FIG. 1,and the other is that an oriented film 4 is formed on a transparentsubstrate 3 as shown in FIG. 2 so that they together function as a basematerial 1 having orientability. The followings are descriptions ofthese cases as the first and second embodiments.

a. First Embodiment

In this embodiment, the base material itself has orientability;specifically, the base material is a stretched film. With a stretchedfilm, the liquid crystal material can be oriented along a stretcheddirection of the film. Therefore, the processing of the base material isaccomplished simply by preparation of a stretched film, which is a meritthat the processing step is made very simple. For the stretched film,any commercially available stretched film can be used, or a stretchedfilm can be made, according to needs, of various materials.

More specifically, examples of the film include films made ofthermoplastic polymers, such as polycarbonate polymers, polyesterpolymers such as polyarylate or polyethylene terephthalate, polyimidepolymers, polysulfone polymers, polyethersulfone polymers, polystyrenepolymers, polyolefin polymers such as polyethylene or polypropylene,polyvinyl alcohol polymers, cellulose acetate polymers, polyvinylchloride polymers, and polymethylmethacrylate polymers, and films madeof liquid crystal polymers.

In this invention, particularly, polyethylene terephthalate (PET) filmis preferably used, because it has a wide range of stretch ratio and isreadily available.

The stretch ratio of the stretched film used in this invention is notlimited to a particular value, as long as the film exhibitsorientability. Thus, even a biaxially stretched film can be used, if thestretch ratio differs between the two axes.

The stretch ratio differs largely depending on the material used, andthere are no particular limits to the stretch ratio. Generally,materials having a 150 to 300% stretch ratio can be used; a preferablerange is 200 to 250%.

b. Second Embodiment

In the second embodiment, the base material having the aboveorientability comprises a transparent substrate and an oriented filmformed thereon.

With this embodiment, there is a merit that selection of the orientatedfilm enables selection of orientation in a relatively wider range ofdirections. Selecting the type of liquid applied on the transparentsubstrate for forming the oriented film allows orientation in variousdirections and enables even more effective orientation.

An oriented film commonly used for a liquid crystal display device orthe like can favorably be used for the oriented film of this embodiment;generally, an oriented film of polyimide that has undergone rubbingtreatment is favorably used.

For the transparent substrate used in this embodiment, any transparentmaterial can be used, e.g., a transparent and rigid material having noflexibility such as silica glass, Pyrex (registered trademark) glass,and synthetic silica glass, or a transparent and flexible material suchas a transparent resin film, and optical resin sheet or the like.

(Patterning of Orientation on the Oriented Film Surface)

In this embodiment, the above oriented film may have a certain patternon the surface thereof. That is, the oriented film may have a patternwith different directions of orientation, including portions orientedin, at least two, different directions.

FIG. 4 is a model view showing an oriented film 4 formed with a patternof different directions of orientation. Arrows 5 in the drawing indicatethe directions of orientation. FIG. 4 shows one example in which theoriented film has a checked pattern, but various other patterns e.g., astriped pattern and the like, may be employed in accordance with thepurposes of use in this invention.

By thus forming a pattern on the oriented film surface with differentdirections of orientation, the phase difference layer comprising aliquid crystal material having refractive index anisotropy providedthereon can have a pattern of refractive index anisotropy conforming tothe pattern on the oriented film surface. As a result, a phasedifference layer laminated body having portions with different phasedifferences in a certain pattern can be obtained, which can be used invarious applications. Patterning on the oriented film surface may beachieved by a rubbing technique using a mask, or in the case of using afilm oriented with the irradiation of light beams, by a mask exposuretechnique or the like.

3. Others

In addition, the phase difference layer laminated body of the inventioncan be formed with other functional layers such as a protective layer orthe like in accordance with the purposes for which the optical elementis to be used.

If the phase difference layer laminated body of the invention is used asa .lamda./4 phase difference layer, it can be used as a circularpolarization plate by bonding a polarization plate thereto with anadhesive layer interposed therebetween.

In this invention, also, as shown in FIG. 6 and FIG. 7, two or morephase difference layers can be laminated. In this case, preferably, thesecond phase difference layer is formed after the formation of anoriented film and rubbing treatment thereof on the first phasedifference layer. The oriented film may be a photo-oriented filminstead.

FIG. 6 shows an example in which a .lamda./2 phase difference layer 13is formed on a glass substrate 11 with an oriented film 12 interposedtherebetween, and a .lamda./4 phase difference layer 14 is furtherformed thereon with another oriented film 12 interposed therebetween. Onthe other hand, FIG. 7 shows an example in which a .lamda./4 phasedifference layer 14 is formed on a glass substrate 11 with an orientedfilm interposed therebetween, and a .lamda./2 phase difference layer 13is further formed thereon with another oriented film 12 interposedtherebetween.

By projecting a linearly polarized beam to this phase difference layerlaminated body from the side of the .lamda./2 phase difference layer 13or a circularly polarized beam from the side of the .lamda./4 phasedifference layer 14, the phase difference layer laminated body canfunction as a broadband phase difference plate shown, for example, inJapanese Patent Laid-Open Publication No. Hei 10-68816. Furthermore, byattaching a polarization plate on the opposite surface of the glasssubstrate 11 with an adhesive layer 15 interposed therebetween as shownin FIG. 6, it can function as a broadband circular polarization plate,with a non-polarized beam incident from the side of the polarizationplate.

Note that, since the fast axes of the .lamda./2 phase difference layer13 and .lamda./4 phase difference layer 14 need to be crossedapproximately at 60.degree. (60.+−.10.degree.), the two oriented filmsshould be inclined to each other approximately at 60.degree.(60.+−.10.degree.). This can be achieved by, for example, changing thedirection of rubbing, or the like.

B. Method for Manufacturing a Phase Difference Layer Laminated Body

A method for manufacturing phase difference layer laminated bodyaccording to the invention is characterized by having:

a base material preparation step of preparing a base material;

an application step of applying a refractive index anisotropic materialhaving an ability of providing refractive index anisotropy on the basematerial for forming a refractive index anisotropic material layer;

an orientation processing step of performing orientation processing tothe refractive index anisotropic material layer; and

an orientation fixing step of fixing the orientation of the refractiveindex anisotropic material layer that has undergone the orientationprocessing in the orientation processing step.

According to the method for manufacturing a phase difference layerlaminated body of the invention, the orientation direction can bedetermined relatively freely in the orientation processing step, thusoffering an advantage that phase difference layers of various differentdirections of fast axis (or slow axis) can be formed.

FIG. 5 shows one example of the method for manufacturing phasedifference layers according to the invention. In this example, a basematerial 1 is first prepared, which includes a transparent substrate 3on which is formed an oriented film 4, as shown in FIG. 5( a) (basematerial preparation step). Next, a refractive index anisotropicmaterial layer 6 comprising a polymerizable liquid crystal material isformed on this base material 1 (application step). This is then letstand under a preset temperature for orienting the polymerizable liquidcrystal material along the direction of orientation of the oriented film(orientation processing step). Next, with a photo mask 7 set thereon, anactivating radiation beam 8 such as ultraviolet light or the like isirradiated, so that energy-radiated portions of the polymerizable liquidcrystal material are cured in a certain pattern (as shown in FIG. 5( c),orientation fixing step), and lastly, it is developed using a solventfor forming the phase difference layer 2 in the certain pattern; a phasedifference layer laminated body having a phase difference layer 2 in apattern on a base material 1 is thus obtained.

The following is a more detailed description of each step of themanufacturing method of the phase difference layer laminated bodyaccording to the invention.

1. Base Material Preparation Step

The first step of the phase difference layer laminated bodymanufacturing method of the invention is the base material preparationstep of preparing a base material.

In this invention, different types of base materials are used dependingon the orienting method in the orientation processing step to bedescribed later. That is, if the refractive index anisotropic materialhaving an ability of providing refractive index anisotropy is a liquidcrystal material and if the orienting method in the orientationprocessing step uses a base material having orientability, then it isnecessary to prepare a base material having orientability. On the otherhand, if another method is to be used for the orientation, then the basematerial need not have orientability.

Base materials having orientability will not be described here sincethey have already been described under the section “2. Base materialhaving orientability” in “A. Phase difference layer laminated body” inthe foregoing.

On the other hand, substrates in the case where no such orientability isrequired may suitably be selected in accordance with the purposes ofuse; since transparency is usually a requirement, a transparent andrigid material having no flexibility such as silica glass, Pyrex(registered trademark) glass, and synthetic silica glass, or atransparent and flexible material such as a transparent resin film, andoptical resin sheet, or the like may be used, for example.

2. Application Step

The next step is the application step of applying a refractive indexanisotropic material having an ability of providing refractive indexanisotropy on the base material.

(Refractive Index Anisotropic Material)

The first example of the refractive index anisotropic material having anability of providing refractive index anisotropy on the base materialused in this invention is a liquid crystal material. The liquid crystalmaterial is not described here since it has already been described underthe section “1. Phase difference layer” in “A. Phase difference layerlaminated body” in the foregoing.

For forming a refractive index anisotropic material layer using apolymerizable liquid crystal material, it is necessary to achievepolymerization using an activating radiation beam in the orientationfixing step to be described later. Depending on the type of theactivating radiation beam, a photopolymerization initiator may be usedas required, for instance in the case of UV curing. Specific examples ofsuch a photopolymerization initiator are Irg 369, Irg 907, Irg 184(trade name) and the like, manufactured by Ciba Specialty ChemicalsCorp.

Refractive index anisotropic materials other than liquid crystalmaterials include materials that form layers and exhibit refractiveindex anisotropy when the molecules are more or less oriented in certaindirections. Any materials that can usually be made to function as aphase difference layer by stretching may be used: Such materials includethermoplastic polymers such as polycarbonate polymers, polyesterpolymers such as polyarylate or polyethylene terephthalate, polyimidepolymers, polysulfone polymers, polyethersulfone polymers, polystyrenepolymers, polyolefin polymers such as polyethylene or polypropylene,polyvinyl alcohol polymers, cellulose acetate polymers, polyvinylchloride polymers, and polymethylmethacrylate polymers.

In this invention, particularly, a refractive index anisotropic materialthat has relatively high polarity is preferable so that it can beoriented by applying a high electric or magnetic field in theorientation processing step to be described later for performingorientation processing. A specific example is a side-chain modifiedphenoxy resin into which 4-nitrophenyl carbamate is introduced.

(Application Method)

In the application step, for example, the above material is dissolved ina solvent or the like to form an application liquid, which is appliedusing various application methods such as spin coating, casting,dipping, bar coating, blade coating, roll coating, spray coating, andthe like.

In the case of the application using a solvent, a drying step isnecessary after the application for removing the solvent.

On the other hand, a refractive index anisotropic material that meltsand liquefies at a temperature at which the material itself does notdecompose or inflict damage on the base material, can be applied in aheated state without solvent. Same application methods as listed abovecan be used in this case, too.

In this invention, the more preferable method for the ease of handlingis the method of dissolving the above-mentioned material in a solventand applying the same. Because a polymerizable liquid crystal materialis favorably used in this invention as noted above, it is particularlypreferable to use a solution of this material as the application liquid.

Any solvents in which the above polymerizable liquid crystal material orthe like can be dissolved, and which do not inhibit the orientability ofthe base material, may be used for this purpose.

Specific examples of solvents include hydrocarbons such as benzene,toluene, xylene, n-butylbenzene, diethylbenzene, and tetralin, etherssuch as methoxybenzene, 1,2-dimethoxybenzene, and diethylene glycoldimethylether, ketones such as acetone, methylethylketone,methylisobutylketone, cyclohexanone, and 2,4-pentanedione, esters suchas ethyl acetate, ethylene glycol monomethyl ether acetate, propyleneglycol monomethyl ether acetate, propylene glycol monoethyl etheracetate, and .gamma.-butyrolactone, amide solvents such as2-pyrrolidone, N-methyl-2-pyrrolidone, dimethyl formamide, anddimethylacetamide, halogenated solvents such as chloroform,dichloromethane, carbon tetrachloride, dichloroethane,tetrachloroethane, trichloroethylene, tetrachloroethylene,chlorobenzene, and ortho-dichlorobenzene, alcohols such ast-butylalcohol, diacetone alcohol, glycerin, monoacetin, ethyleneglycol, triethylene glycol, hexylene glycol, ethylene glycol monomethylether, ethyl cellosolve, and butyl cellosolve the like, phenols such asphenol, and para-chlorophenol; these can be used either alone or incombination.

The solubility of the polymerizable liquid crystal material or the likemay not be sufficient, or the above substrate having orientability maybe corroded with the use of a single type of solvent. Such troubles canbe avoided by using a mixture of two or more types of solvents. Amongthe above-listed solvents, hydrocarbon solvents and glycol mono etheracetate solvents are favorably used alone, while ethers and ketones arefavorably used in mixture with glycols. There is no generic ruleregarding the concentration of the solution because it should bedetermined depending on the solubility of liquid crystal compositionsand the film thickness of phase difference layers to be fabricated; itis, however, usually within a range of 1 to 60% by weight, and morepreferably 3 to 40% by weight.

In this invention, there may be cases where the phase difference layershould preferably be formed in a certain pattern on the substrate asdescribed above. In such a case, a nozzle discharge technique such as aninkjet method or the like, or a printing technique such as photogravureor the like may be employed in this application step for patternedapplication. In the case where a highly precise pattern is needed, thebase material may undergo a preparatory step of forming a patternconsisting of hydrophilic regions and water-repellent regions for givingwettability, the patterned application being made to the hydrophilicregions.

3. Orientation Processing Step

The next step, in this invention, is the orientation processing step ofperforming orientation processing to the refractive index anisotropicmaterial layer applied on the base material. The orientation processingstep according to the invention includes two methods: One method uses abase material having orientability, the other achieves orientation byapplying force to molecules of the refractive index anisotropicmaterial. Each method is respectively described below.

(Method Using a Base Material Having Orientability)

This method using a base material having orientability can be employedin the orientation processing step of the invention when theabove-described liquid crystal material is used for the refractive indexanisotropic material.

In the case of using a base material having orientability, therefractive index anisotropic material, or the liquid crystal material inthis case, formed on the base material having orientability is heated toa temperature at which it can form a liquid crystal phase, thetemperature being maintained the same until the liquid crystal materialis oriented along directions defined by the base material.

The temperature and duration of time for which it is maintained dependlargely on the liquid crystal material used and the orientability of thebase material; they should suitably be set in accordance with the typesof the liquid crystal material and base material having orientability.

Incidentally, a base material comprising a transparent substrate and anoriented film formed thereof to have orientability can be used withfavorable results because of a wider range of selection of orientationdirection or the direction of fast axis (or slow axis) of phasedifference layer, and because the use of the oriented film makespossible to give a pattern to the orientation directions, as has beendescribed under the section “2. Base material having orientability” in“A. Phase difference layer laminated body” in the foregoing.

(Orienting Method with Application of Force to Molecules)

In this invention, apart from the method using a base material havingorientability, the refractive index anisotropic material having anability of providing refractive index anisotropy can be oriented by amethod of applying force to molecules.

In this orienting method of applying force to molecules, after heatingthe refractive index anisotropic material formed on the base material inthe above application step to a temperature at least exceeding atemperature Tg at which molecules are movable inside the layer, force isapplied to the molecules to orient them in certain directions.

Examples of such a force applying method include a method of applying apowerful electrostatic field, and a method of applying a powerfulmagnetic field, and the like.

While the above method using a base material having orientability canuse only a liquid crystal material as the refractive index anisotropicmaterial, this method can employ, not only liquid crystal materials, butalso any material that has an ability of providing refractive indexanisotropy.

If an electrostatic field is to be used, for example, for applying aforce to the molecules, a refractive index anisotropic material having amolecular structure that can receive a force induced by an electrostaticfield may be used; specifically, a material having polarity may be used.Similarly, if a magnetic field is to be used, a refractive indexanisotropic material having a molecular structure that can receive aforce induced by a magnetic field may be used; in this case also, amaterial having polarity may be used. The material, in this case, shouldhave refractive index anisotropy as well as polarity, but it should notbe limited to a polymer material; for example, a polymerizable monomeror oligomer may also be used. Any material can be used as long as itexhibits refractive index anisotropy by polymerization by, e.g.,irradiation of an activating radiation beam in a state where themolecules are oriented by an electric or magnetic field.

According to this method, the orientation direction, i.e., the directionof fast axis (or slow axis) of phase difference layer, can readily bechanged, e.g., by control of the position of an electromagnetic ormagnetic field. Orientation is therefore possible in any direction,whereby the resultant phase difference layer laminated body has a meritthat it can be used in a very wide range of applications.

4. Orientation Fixing Step

In this invention, an orientation fixing step is carried out for fixingthe given orientation of the refractive index anisotropic material layerthat has undergone the above orientation processing.

This orientation fixing step may be performed along with the orientationprocessing step, or after the orientation processing step has beencompleted. If, for example, the above orientation processing stepemploys a method using an electrostatic field, then the orientationfixing step, in which temperature is lowered in this case, may beperformed while applying the electrostatic field.

In this invention, the orientation fixing step is carried out indifferent manners depending on the refractive index anisotropic materialbeing used. Specifically, there are two cases; one is that therefractive index anisotropic material is a polymerizable material, andthe other is that it is a non-polymerizable polymer material. Bothcases, wherein the refractive index anisotropic material is apolymerizable material, and a non-polymerizable polymer material, areseparately described below.

(Polymerizable Material)

In this invention, for the refractive index anisotropic material,polymerizable liquid crystal materials such as polymerizable monomers,polymerizable oligomers, and polymerizable liquid crystal polymers arepreferably used as noted above.

In the orientation fixing step in which such a polymerizable liquidcrystal material is used, an activating radiation beam, which promotespolymerization, is irradiated to the refractive index anisotropicmaterial layer comprising the polymerizable liquid crystal materialformed on the base material having orientability.

Activating radiation beam” mentioned in this invention means radiationrays that are capable of inducing polymerization in a polymerizablematerial, which may contain, if required, a polymerization initiator.

In this invention, a preferable method is that UV ray is used as theactivating radiation beam for a polymerizable liquid crystal material,which contains a polymerization initiator that generates radicals forinducing radical polymerization upon irradiation of the UV rays. This isbecause the method using UV ray as the activating radiation beam is awell-established technique including the polymerization initiator usedtherewith, and can readily be applied to this invention.

This orientation fixing step with irradiation of an activating radiationbeam may be performed at the same processing temperature as that in theabove orientation processing step, i.e., the temperature at which thepolymerizable liquid crystal material transforms into a liquid crystalphase, or lower than that. A temperature drop after the polymerizableliquid crystal material has transformed into a liquid crystal phase doesnot cause a disorder in the orientation.

Other polymerizable materials that have no liquid crystal properties mayalso be used for the polymerizable material as noted above; theorientation fixing step can be performed similarly in this case, too.

(Non-Polymerizable Polymer Material)

The refractive index anisotropic material having an ability of providingrefractive index anisotropy can be a non-polymerizable polymer materialwhen, for example, it is a liquid crystal material other than theabove-mentioned polymerizable liquid crystal materials, i.e., one ofcommonly known non-polymerizable liquid crystal polymers.

The orientation fixing step in the case of using such a liquid crystalpolymer is a step of lowering the temperature at which the polymertransforms into a liquid crystal phase to the temperature at which thepolymer transforms into a solid phase. In the above orientationprocessing step, by the orientation processing, the liquid crystalpolymer has transformed into a liquid crystal phase having a nematicstructure along the orientation defined by the base material havingorientability. In this state, by setting the temperature at which liquidcrystal transforms to a glass state, the polymer can be made into aphase difference layer having, as a whole, refractive index anisotropy.

On the other hand, if the above orientation processing step employs anorienting method with application of force to molecules, fixing of theorientation of molecules can similarly be achieved by lowering thetemperature in the oriented state. Thereby, a phase difference layerhaving, as a whole, refractive index anisotropy can be obtained. Thetemperature, in this case, should preferably be lowered to a level lowerthan the glass transition temperature Tg.

(Patterning of Phase Difference Layer)

In this invention, depending on the purposes of use, the phasedifference layer formed on the base material may be required to have acertain pattern, as mentioned above. Patterning may be achieved in theabove application step as described above, but in terms of patternprecision, it is preferable to perform the patterning in thisorientation fixing step. That is, in the case of using theabove-mentioned polymerizable material, patterning of the phasedifference layer can readily be achieved by irradiation of theactivating radiation beam in a pattern for forming polymerized portionsin a pattern, followed by a development step using a solvent or thelike.

Examples of solvents that can be used for the development includeacetone, 3-methoxybutyl acetate, diglyme, cyclohexanone,tetrahydrofuran, toluene, methylene chloride, and methyl ethyl ketone orthe like.

A favorable method of irradiating the material with the activatingradiation beam in a pattern is a method using a photo mask as shown inFIG. 5, but it is not limited to this; a laser beam, for example, may beused as the activating radiation beam, the irradiation being performedas if to draw a line.

In this invention, if the development is performed using the solvent orthe like thereafter, then it is preferable that the cured portions ofthe polymerizable liquid crystal material have cured to a degree of 85%by the above activating radiation beam. Thereby, deterioration ofoptical characteristics of the cured portions or swelling thereof duringthe development thereafter using a solvent are effectively prevented.

In the case of using a non-polymerizable material, on the other hand,patterning may be achieved by a photolithography technique using aphotoresist.

5. Others

By the above orientation fixing step, a phase difference layer laminatedbody having a phase difference layer on the base material is obtained:In this invention, further, other functional layers such as a protectivelayer may be added according to needs.

Also, if the phase difference layer laminated body of the invention is a.lamda./4 phase difference layer, a further step may be included forbonding a polarization plate with an adhesive layer thereto. Thereby,circular polarization plates can be fabricated.

Furthermore, since the phase difference layer laminated body may havetwo or more laminated phase difference layers as shown in FIG. 6 andFIG. 7, the above application step, orientation processing step, andorientation fixing step may be repeated twice or more. If theorientation processing is achieved by the use of an oriented film aswith the examples shown in FIG. 6 and FIG. 7, it is preferable toperform an oriented film formation step after the orientation fixingstep.

C. Liquid Crystal Display Device

The liquid crystal display device of the invention is characterized bythe use of a phase difference layer laminated body described in thesection “A. Phase difference layer laminated body” above, andparticularly, a preferable embodiment is a liquid crystal display deviceusing a phase difference layer laminated body having the phasedifference layer formed in a pattern on the base material.

As described above, the phase difference layer laminated body using apolymerizable liquid crystal material, particularly a polymerizableliquid crystal monomer, can readily be formed with a phase differencelayer formed on the base material in a highly precise pattern, bypatterned irradiation of an activating radiation beam using, e.g., aphoto mask, in the orientation fixing step; a liquid crystal displaydevice in which is incorporated such a phase difference layer laminatedbody having a phase difference layer in a highly precise pattern willhave an unrivaled high quality.

One example of a liquid crystal display device is a three-dimensionalliquid crystal display device shown, for example, in Japanese PatentLaid-Open Publication No. Hei 9-304740; the phase difference layerlaminated body having a patterned phase difference layer on a basematerial may be used for the phase difference plates of this device thatcover the entire liquid crystal display panel in a striped manner.

Another example is a projection type display device shown, for example,in U.S. Pat. No. 5,956,001 (Japanese Patent Laid-Open Publication No.Hei 8-234205); the phase difference layer laminated body having apatterned phase difference layer on a base material may be used for the.lamda./2 phase difference plates formed in a pattern in this projectiontype display device.

Referring now to FIG. 8, a configuration and a production method of aliquid crystal display panel 111 in a three-dimensional liquid crystaldisplay device 100 will be described.

Scanning lines, signal lines, pixel electrodes (these not shown), andTFT elements 104 are formed on a glass substrate 102 a. Pixel electrodesare provided one each for each of the pixels 103 arrayed in a matrix.The scanning lines are formed along a horizontal direction of thedisplay screen of the liquid crystal display panel 111 such that eachscanning line corresponds to one line of pixels 103, while the signallines are formed orthogonally to the scanning lines, each signal linecorresponding to one row of pixels 103. The scanning lines, signallines, and pixel electrodes are connected to each other by the TFTelements 104.

The matrix-arrayed pixels 103 are divided into a right-eye pixel group103 (r) and a left-eye pixel group 103 (l) for each line of pixels. Theright-eye pixel group 103 (r) and left-eye pixel group 103 (l) arealternately arranged for each of the scanning lines.

Next, an oriented film 105 a is formed on the entire surface of theglass substrate 102 a provided with the TFT elements 104.

On a counter glass substrate 102 b are formed a color filter 108 a, anda black matrix 108 b for shielding the TFT elements 104 formed on theglass substrate 102 a from light.

In this embodiment, the color filter 108 a was formed such that thefilter portions of respective colors R, G, and B forming the colorfilter 108 a are arranged in stripes parallel to the signal lines, andsuch that R, G, and B are arranged in a cyclic pattern in the scanningline direction (horizontal direction in the screen). The black matrix108 b was formed in a lattice pattern so that each pixel is surrounded.A transparent conductive film such as ITO used as transparent electrodes115 is formed on the entire surface of the substrate 102 b over thecolor filter 108 a by sputtering, and further, an oriented film 105 b isformed thereon similarly to the oriented film 105 a. The countersubstrate is thus formed.

Successively, the substrate on the TFT side and counter substrateprepared as described above respectively undergo a rubbing process,after which both substrates are bonded together with a spacer 107 tokeep a constant distance between them. Next, liquid crystal is injectedin a vacuum in between the substrates to form a liquid crystal layer112. The liquid crystal display panel 111 is completed through the aboveprocess steps. In this embodiment, the display mode of the liquidcrystal display panel 111 is a TN display mode.

Here, a polarization plate 101 b having the same polarization axis overthe entire surface is provided so as to adjoin the glass substrate 102 bof the liquid crystal display panel 111 in the liquid crystal displaydevice 100. Successively, phase difference layer laminated bodies 106 aand 106 b are provided alternately in stripes on the polarization plate101 b for each of the scanning lines. That is, the phase differencelayer laminated bodies 106 a and 106 b are arranged alternately for eachline of pixels such that they each have a width corresponding to oneline of pixels aligned along the horizontal direction. Accordingly, asum of a number of the stripe phase difference layer laminated bodies106 a and 106 equal to a number of TV scanning lines. The slow axis ofthe phase difference layer laminated body 106 a is oriented at 45° tothe polarization axis of the polarization plate 101 b, while the slowaxis of the phase difference layer laminated body 106 b is oriented at45° in the opposite direction of the slow axis of the phase differencelayer laminated body 106 a to the polarization axis of the polarizationplate 101 b.

The pixels 103 arrayed in a matrix and the phase difference layerlaminated body 106 a, 106 b are formed in an equal pitch in thedirection orthogonally to the scanning line.

In this embodiment, the phase difference layer laminated bodies 106 aand 106 b are both quarter wave plates. Therefore, the light that passesthrough the polarization plate 101 b and the phase difference layerlaminated bodies 106 a and 106 b after being emitted from the liquidcrystal display panel 111 is circularly polarized light wherein thepolarization directions are at right angles to one another alternatelypixel row by pixel row. A viewer 113 can view a three-dimensional imageeven when he/she tilts his/her head by wearing circular polarizationglasses 110 having polarization plates 110 a and 110 b corresponding torespective circular polarization directions.

Next, referring to FIG. 9, a method of patterning a photo-oriented filmin the phase difference layer laminated bodies provided alternately instripes for each scanning line in the above-described liquid crystaldisplay panel 111 will be described.

Such phase difference layer laminated bodies are patterned by exposurethrough a mask using a photo-oriented film that is oriented by light.

FIG. 9 illustrates a production method wherein the stripe pattern suchas the one mentioned above is formed continuously on the photo-orientedfilm.

Reference numeral 122 in FIG. 9 denotes a roll of an oriented film, 124a photo mask, and 126 a roll of a photo mask, respectively.

Reference numeral 128 denotes a patterning/exposure part having anelongated light source 128A for patterning the photo-oriented film byexposure. Reference numeral 130 denotes a photo mask take-up roll fortaking up the photo mask 124 after it has passed through thepatterning/exposure part 128. Reference numeral 132 denotes a solidexposure part having an elongated light source 132A for exposing theoriented film 120 after it has passed through the patterning/exposurepart 128. Reference numerals 134A and 134B denote nip rolls, and 136A to136E guide rolls, respectively.

Here, the photo-oriented film has photosensitivity at a wavelength inthe UV light region, and the photo mask 124 includes a UV lighttransmissive film formed with a patterned light shielding film.

The photo mask 124 has the patterned light shielding film formedcorrespondingly to one of the above-described stripe phase differencelayer laminated bodies 106 a and 106 b such that light-shieldingportions having a width corresponding to one line of pixels andlight-transmitting portions having a width corresponding to one line ofpixels are formed alternately and linearly such as to adjoin each other,continuously in the lengthwise direction of the film. Here, a sum of anumber of the light-shielding portions correspondingly to one of thestripe phase difference layer laminated bodies 106 a and 106 b and anumber of the non-light shielding portions equals to a number of TVscanning lines.

Next, the process step of continuously exposing the photo-oriented film120 will be explained.

The oriented film 120 and the photo mask 124 are respectively drawn outfrom the roll 122 of the oriented film and the roll 126 of the photomask, passed through between the nip rolls 134A and 134B so as to movethem continuously in a horizontal orientation in an overlapped manner.

Here, the photo mask 124 is overlapped on the underside of the orientedfilm 120, and UV rays of the photosensitive wavelength of thephoto-oriented film are irradiated from below by the patterning/exposurepart 128. In this step, exposed parts of the photo-oriented film areexposed 100% to the UV rays from the patterning/exposure part 128 sothat there is left no unexposed portions therein.

Next, the photo mask 124 exiting from between the nip rolls 134B istaken up on the photo mask take-up roll 130 positioned diagonally belowthe nip rolls 134B. The oriented film 120, on the other hand, afterpassing through the nip rolls 134B, is wound on the guide roll 136Bthereabove, thereby being separated from the photo mask 124.

Next, when the film passes under the pair of horizontal guide rolls 136Cand 136D, UV rays of the photosensitive wavelength of the photo-orientedfilm are irradiated from the solid exposure part 132, so thatnon-exposed portions corresponding to the light-shielding portions ofthe photo mask 124 are exposed.

Here, the patterning/exposure part 128 and the solid exposure part 132include a linear polarization plate 129 and 133 having polarization axesoriented at 90° to each other, respectively, so that stripe portionsexposed at the patterning/exposure part 128 and stripe portions exposedat the solid exposure part 132 in the photo-oriented film haveorientation directions that are oriented at 90° to each other.

After being exposed at the solid exposure part 132, the oriented film120 is fed, via the guide rolls 136D and 136E, to a process step ofapplying crystal liquid material.

Yet another preferred embodiment is a liquid crystal display device 50shown in FIG. 10 to FIG. 11, including the following: A liquid crystaldisplay element 56 including a liquid crystal layer 52 and a pluralityof unit cells 54 that constitute a multiplicity of pixels, liquidcrystal molecules on the surface of the liquid crystal layer 52 beingoriented with a plurality of different directors in directions indicatedby arrows in FIG. 12 in each of the unit cells 54; and phase differencelayers (phase difference optical elements) 60 arranged on both sides inthe thickness direction of the liquid crystal display element 56, thephase difference layers divided into a plurality of (four in thisembodiment) oriented compensation regions 58A, 58B, 58C, 58D inaccordance with the directions of the liquid crystal directors in eachunit cell 54, the liquid crystal substance being oriented and fixed ineach of the oriented compensation regions 58A, 58B, 58C, 58D.

The liquid crystal display element 56 is an MVA type; it has the liquidcrystal layer 52 sealed between a pair of oriented films 62, 63, asshown in FIG. 11. Reference numerals 66, 68, and 70 denote transparentelectrodes, transparent base material, and polarization plates,respectively.

Further, as shown in FIG. 12, the liquid crystal molecules on thesurface of the liquid crystal layer 52 are oriented with the directorsin symmetric directions relative to the center of each unit cell 54.Specifically, one of the oriented films 62 is formed with asemi-spherical rib 62A protruded at the center of each cell 54, as shownin FIG. 11, and the liquid crystal molecules on the surface of theliquid crystal layer 52 are oriented at angles radiating from the rib62A.

Each unit cell 54 has four oriented compensation regions 58A, 58B, 58C,58D that are defined by dividing the unit cell 54 into a plurality of(four in this embodiment) sections with an equal angular spacing aroundthe center, and the liquid crystal substance divided into these orientedcompensation regions 58A, 58B, 58C, 58D is oriented and fixed.

By thus orienting the molecules in the phase difference layer 60 foreach of the oriented compensation regions 58A, 58B, 58C, 58D inaccordance with the directions of the liquid crystal directors of theliquid crystal layer 52, optical compensation is made possible in moreprecise and various ways than conventionally practiced, whereby theproblem of viewing-angle dependency is much improved and high-qualityimage display is realized.

Divisional orientation and fixation of the liquid crystal substance toform the oriented compensation regions may be achieved either by coatinga liquid crystal substance having nematic properties on the substrateand orienting it in a certain direction using an electrostatic ormagnetic field, followed by a fixing step of irradiating UV rays or thelike using a photo mask, these steps being repeated for each of theoriented compensation regions; or, by coating the liquid crystalsubstance on an oriented film that has been processed to have differentorientation directions for each of the oriented compensation regions bya mask rubbing technique, followed by fixing of the liquid crystal inthe oriented state.

In this embodiment, the liquid crystal molecules on the surface of theliquid crystal layer 52 are oriented with the directors in symmetricdirections relative to the center of each unit cell 54, but, as shown inFIG. 13, one alternative is to divide each unit cell 54 of the liquidcrystal display element 56 into a plurality of (four in this embodiment)oriented display regions 72A, 72B, 72C, 72D, the liquid crystalmolecules on the surface of the liquid crystal layer 52 being orientedin respective directions of the oriented display regions 72A, 72B, 72C,72D, and to form the oriented compensation regions 58A, 58B, 58C, 58Dcorrespondingly to the oriented display regions 72A, 7213, 72C, 72D.

Orientation processing of the oriented film to form the oriented displayregions 72A, 72B, 72C, 72D with different orientation directions may beachieved by the use of a square pyramid rib, or by a knownphoto-oriented film method or the like.

By thus orienting the molecules in the phase difference layer for eachof the oriented compensation regions in accordance with the orientationof liquid crystal molecules of each of the oriented display regions,even more precise optical compensation can be realized.

In the above embodiment, each unit cell 54 of the liquid crystal displayelement 56 is divided into four oriented display regions, but theinvention is not limited to this; for example, a triangular prism orpyramid rib may be formed on the oriented film to divide each unit cellof the liquid crystal display element into two or three oriented displayregions, or, a polygonal pyramid rib of more than five base sides may beformed on the oriented film to divide each unit cell of the liquidcrystal display element into five or more oriented display regions. Itgoes without saying that the effect of improving display quality is alsoobtained in these cases.

Incidentally, the semi-spherical rib 62A mentioned above divides eachunit cell of the liquid crystal display element into an infinite number,as it were, of oriented display regions.

Similarly, each unit cell of the phase difference layer may be dividedinto two or three oriented compensation regions, or it may be dividedinto five or more oriented compensation regions.

In the above embodiment, the phase difference layer 60 has four orientedcompensation regions 58A, 58B, 58C, 58D corresponding to the fouroriented display regions 72A, 72B, 72C, 72D of the unit cell 54 of theliquid crystal display element 56, but the invention is not limited tothis; a plurality of oriented compensation regions of opticalcompensation elements may be provided relative to one oriented displayregion in the unit cell. Thereby, even more precise and variant opticalcompensation can be realized.

Also, although the phase difference layers 60 are arranged on both sidesin the thickness direction of the liquid crystal display element 56 inthe above embodiment, the invention is not limited to this; the phasedifference layer may be arranged only on one side in the thicknessdirection of the liquid crystal display element, depending on the mannerin which optical compensation is carried out.

Also, although the liquid crystal display element 56 is an MVA type inthe above embodiment, the invention is not limited to this; theinvention can obviously be applied to other types of liquid crystaldisplay elements including other VA types such as a PVA type, and TNtype, STN type, IPS type, OCB type, and ECB type or the like.

Furthermore, the invention should not be limited to the above-describedembodiments, which were given only by way of example; the technicalscope of the invention includes any other constructions substantiallyidentical to and having similar effects as those of the technical ideasdefined by the claim of the invention.

For example, while the material used for the phase difference layer hasbeen described as a liquid crystal material that can form a nematicphase under the section “A. Phase difference layer laminated body”above, any liquid crystal material that does not form a cholestericphase can be used without any problems in this invention; thus a liquidcrystal material that forms a smectic phase should also be included inthe definition of liquid crystal in this invention.

Example

An example will be described below for further explanation of theinvention.

A solution of polymerizable liquid crystal monomer in toluene wasprepared, the monomer having a mesogen in the center, polymerizableacrylate at either end, and a spacer linking therebetween, and having aliquid crystal-isotropic transition temperature (temperature at whichliquid crystal transforms into an isotropic phase) of 100.degree. C.Note that, a photopolymerization initiator (Irg 184: Ciba SpecialtyChemicals Corp.) was added to the above solution in toluene in an amountof 5% by weight relative to the monomer molecules.

Meanwhile, polyimide was applied on a glass substrate to form a coat,which then underwent rubbing treatment in certain directions, to form anoriented film.

This glass substrate with the oriented film was then set in a spincoater, and the above solution in toluene was applied onto the orientedfilm to a thickness of about 5. mu.m by spin coating.

Next, the substrate was heated at 80.degree. C. for one minute tovaporize toluene in the solution, after which it was confirmed that theliquid crystal film (uncured liquid crystal film) formed on the orientedfilm was in a nematic phase.

UV rays were then irradiated at 100 mJ/cm.sup.2 to the uncured nematicliquid crystal film by a UV irradiation apparatus, with the use of aphoto mask having openings in a certain pattern. The UV irradiationintensity was set so that UV-irradiated portions of the nematic liquidcrystal film would polymerize (cure) to a degree of 90% or more.

Thereafter, the glass substrate with the oriented film formed with thenematic liquid crystal film was immersed in acetone with rocking motionapplied thereto for one minute so as to remove uncured portions of thenematic liquid crystal film.

Finally, the above glass substrate was taken out from acetone and dried;a phase difference layer laminated body having a phase difference layerwith a desired pattern was thus fabricated, the nematic liquid crystalfilm being formed in UV-irradiated portions, while the oriented filmbeing exposed in other portions.

Incidentally, the nematic liquid crystal film formed in this example hada substantially uniform film thickness of 1.5. mu.m, and the pattern wasformed with a very high degree of precision.

INDUSTRIAL APPLICABILITY

According to the present invention, a liquid crystal material that canform a nematic phase is used for forming a phase difference layer in apattern, and orientation directions are readily determined by selectingthe type of liquid crystal materials and base materials havingorientability; thus the invention provides a phase difference layerlaminated body that can be applied to a three dimensional liquid crystaldisplay device.

What is claimed:
 1. A method for manufacturing a phase difference layer laminated body used in a three-dimensional liquid crystal display device, wherein unit cells are divided into groups for left and right eyes, which are given different degrees of polarization, thereby creating a three-dimensional image, characterized by having: a base material preparation step of preparing a base material; an application step of applying a refractive index anisotropic material having an ability of providing refractive index anisotropy on the base material for forming a refractive index anisotropic material layer; an orientation processing step of performing orientation processing to the refractive index anisotropic material layer so as to form a pattern with two portions oriented in two different directions; an orientation fixing step of fixing the orientation of the refractive index anisotropic material layer that has undergone the orientation processing in the orientation processing step.
 2. The method for manufacturing a phase difference layer laminated body according to claim 1, wherein the base material is a base material having orientability, the refractive index anisotropic material is a liquid crystal material that can form a nematic phase, and the orientation processing step is a step of maintaining the refractive index anisotropic material layer in a temperature at which the liquid crystal material transforms into a liquid crystal phase.
 3. The method for manufacturing a phase difference layer laminated body according to claim 2, wherein the liquid crystal material is a material having at least one of a polymerizable liquid crystal monomer, a polymerizable liquid crystal oligomer, and a polymerizable liquid crystal polymer, and wherein the orientation fixing step is a step of irradiating, with an activating radiation beam, the material having at least one of the polymerizable liquid crystal monomer, the polymerizable liquid crystal oligomer, and the polymerizable liquid crystal polymer for polymerization thereof.
 4. The method for manufacturing a phase difference layer laminated body according to claim 2, wherein the liquid crystal material is a polymerizable liquid crystal monomer.
 5. The method for manufacturing a phase difference layer laminated body according to claim 3, wherein the activating radiation beam irradiation step is a step of irradiating the material with the activating radiation beam in a pattern, and wherein the method further comprises a development step of developing unpolymerized portions of the liquid crystal material, after the step of irradiating the material with the activating radiation beam in the pattern.
 6. The method for manufacturing a phase difference layer laminated body according to claim 2, wherein the base material having orientability is obtained by forming an oriented film on a transparent film.
 7. The method for manufacturing a phase difference layer laminated body according to claim 3, wherein the oriented film is formed in a pattern with portions that are oriented in two different directions, and wherein the liquid crystal material on the oriented film has refractive index anisotropy that conforms to the two directions of orientation of the oriented film.
 8. The method for manufacturing a phase difference layer laminated body according to claim 7, wherein the two directions of orientation of the oriented film are 45° and 45° in a counter direction respectively with respect to scanning lines of the three-dimensional liquid crystal display device.
 9. The method for manufacturing a phase difference layer laminated body according to claim 7, wherein the two directions of orientation of the oriented film are parallel and perpendicular respectively with respect to scanning lines of the three-dimensional liquid crystal display device.
 10. A method of manufacturing an oriented film, comprising: a patterning exposure step of exposing a surface of a photo-oriented film through a photo mask to linearly polarized light; and a second exposure step of exposing portions of the patterned photo-oriented film that were not exposed in the previous patterning exposure step to second linear polarization light having a polarization axis oriented at 90° to a polarization axis of the linear polarization light used in the previous step.
 11. The method of manufacturing an oriented film according to claim 10, wherein the photo-oriented film is formed by being applied on an oriented film, the photo mask comprising a light transmitting film formed with a light-shielding pattern comprising light shielding portions and non-light shielding portions, the light transmitting film transmitting light of a photosensitive wavelength of the photo-oriented film, and wherein the method further comprises a step of overlapping the photo mask on the oriented film before the patterning exposure step; and a step of separating the photo mask from the photo-oriented film after the patterning exposure step.
 12. The method of manufacturing an oriented film according to claim 11, wherein the light-shielding pattern of the photo mask is formed with light shielding portions and non-light shielding portions alternately and in parallel with an equal width, so that, in the second exposure step, parallel linear exposed portions that correspond to the non-light shielding portions are patterned on the photo-oriented film.
 13. The method of manufacturing an oriented film according to claim 12, wherein the light shielding portions and the non-light shielding portions therebetween in the light shielding pattern have the same width, and wherein a sum of a number of stripe light shielding portions and a number of the non-light shielding portions equals to a number of TV scanning lines. 